1. Field of the Invention
The invention concerns an apparatus for the severing of the fillets from the fishbone skeleton of fish conveyed tail forwards in a conveying direction, comprising belly and back filleting knives and severing knives, all of these arranged essentially in pairs, tools for cutting the ribs free arranged essentially in pairs between the belly and the back filleting knives on the one hand and the severing knives on the other hand as well as respective belly and back guides arranged in pairs and extending in the planes of the belly and back filleting knives and downstream of these in the conveying direction.
2. Description of Prior Art
The filleting of fish usually takes place through filleting cuts conducted over the entire fish at both sides of the belly and back spokes and subsequent severing of the fillets from the ribs and vertebral appendages through rib cuts conducted above the same as far as the plane of the back filleting cuts. In that case, the rib knife is activated on arrival of the abdominal cavity end through freeing of the effective cutting edges. The complete detaching of the fillets takes place finally through a pair of severing cuts, which are conducted to both sides of the backbone and by means of which the flesh bands remaining between the belly and back filleting cuts are severed.
Such a filleted apparatus is for example known from the DE-PS 14 54 087 which also shows the cut-backing supports holding the cutting edges of the rib knives concealed until the arrival of the abdominal cavity end and arranged to be deflected then. In that case, belly and back guides arranged directly downstream of the belly and back filleting knives and in their planes take over the guiding of the fish, in that these enter into the filleting cuts each reaching the backbone. In consequence of the rigid arrangement of the rib cutting tool in a plane touching the lower edges of the back guides, the tail part, not to be processed by this tool, of the fish with its belly-sided fillets cut free by the belly filleting knives is guided away over the rib knives. In order to give the tail part the deviatability in height necessary for this action, the back guides are at first held raised and are lowered only with the freeing of the cutting blades of the rib knives on arrival of the abdominal cavity end.
Due to the circular shape of the knives, there results the disadvantage in such a filleting device that there is a measurable loss of yield at the abdominal cavity end by the necessity of the cutting edges of the rib knives having to be freed already when the first rib arches reach the preceding parts of the cutting edges. Beyond that, a rough cutting surface arises in this region due to the motion of the fish, taking place during the lowering of the back guides, transversely to the knives during the cutting process, which is disadvantageous for optical reasons as well as also from a bacteriological point of view.
To improve the yield in fillet flesh, scraper tools as disclosed in the DE-PS 13 54 089 have come into use as rib cutting tools. The improvement in yield in that case rests on the fact that the scraper knives scrape by their cutting edges directly over the surface of the ribs or vertebral appendages so that no fillet flesh remains on these. With the use of such scraper tools, a pre-disposition of the severing cut for the severing of the flesh bands remaining at the sides of the backbone after the belly and back filleting cuts is required before the rib cut, because the scraper knives lying rigidly in the plane of the lower edges of the back guides in consequence of their ploughlike effect push the fillets away from the ribs or vertebral appendages. For this, the fillets must however be completely detached in the tail region.
In such a cutting sequence, it is apparent that due to the upsetting forces acting on the fillets in this region, irregularities in the cut conduction arise, which impair the filleting result qualitatively and with respect to yield. Beyond that, it is not possible to ensure that the severed fillets are always delivered in unambiguous position, for example planarly lying on the skin side. This is however a prerequisite for a problem-free automatic further processing which has the object for example of skinning.